Notify Observer Missing on Decorators created in Blueprints

Development Programming & Scripting Blueprint
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1

I’m having some trouble with decorators in Behavior Trees. When I create a new decorator using Blueprints, it’s missing the “Notify Observer” option in Flow control.

For example the standard decorator “Blackboard” has these options, but the decorator I created doesn’t appear to have them.

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The BTD_TestBool task nis pretty straightforward, but If I missed something that would have enabled those options please let me know.

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Functionally, I’m not able to interrupt a MoveTo node using my custom decorator, but I can with the Standard “Blackboard” decorator. Does anyone have a workaround for this?

2

I know it has been quite a while, but did you ever discover what was causing this issue? I’m trying to interrupt a wait node however the “Notify Observer” option is missing.

3

This still seems to be impossible in 4.11.2. Anyone from Epic able to help out here?

4

same in 4.17.1

5

Same issue here, any sign of an answer?

6

When creating your own decorators, you’ll need to set 3 variables in the constructor in order to enable the “aborting” dropdown you’re looking for. I’ve used the following constructor when I wanted to have a “Does Path Exist” decorator that would abort the underlying tree when it failed:

UAI_DoesPathExistAborting::UAI_DoesPathExistAborting(const FObjectInitializer& ObjectInitializer) : Super(ObjectInitializer)
{
	bAllowAbortLowerPri = true;
	bAllowAbortNone = true;
	bAllowAbortChildNodes = true;
	FlowAbortMode = EBTFlowAbortMode::None;
}

I don’t believe that it’s possible to do this via Blueprints, so you should have to use c++.

7

I’m also stuck here on 4.18

8

you might want to check my answer below if you’re willing to employ a small amount of c++

9

Ohh okay yeah, that’s no problem I just glanced over it. Didn’t notice the last line. Thanks.

10

What is your parent class for the C++ class? Do you use BTDecorator or BTDecorator_Blackboard? Or something else? Thanks again.

11

You can use either, depending on what you’re after. BTDecorator_BlackboardBase just gives you a “default” blackboard key to edit. It’s useful when your decorator will only have a single parameter.

12

This still didn’t give me the “Notify Observer” drop down. It just gave me the “Observer Reports” drop down, which was already there.

13

Could this be done with UE 5.0 by blueprint ?